Pressure operated regulator for burners



Feb. 25, 1956,

W. E. JOHNSTON 2,32,2833 PRESSURE OPERATED REGULATOR FOR BURNERS Filed June 18, 1932 5 Sheets-Sheet l I 1 I I I I I M Im'h III INVENTOR MYm fi/z f. Jam/570M Q ORNEY H Mb. 25, E1936, W. E. JOHNSTON 2,32,2$3

PRESSURE OPERATED REGULATOR FOR BURNERS Filed June 18, 1932 5 Sheets-Sheet 2 FeFm. 25 3936. w. E, JOHNSTON PRESSURE OPERATED REGULATOR FOR BURNER-5 Filed June 18, 1932 5 Sheets-Sheet 3 F INVENTOR V/fl YEA/F? 5. dam 5 TOM ATTORNEYS Feai vo 25, 119%, w. E. JOHNSTON PRESSURE OPERATED REGULATOR FOR BURNERS Filed June 18, 1932 5 Sheets-Sheet 4 N 4 MM M EM 0 Y J E R. N m%m myy n NW A mm W. E. JOHNSTON PRESSURE OPERATED REGULATOR FOR BURNERS Feb 25, 119%.

Filed June 18, 1932 E 5 Sheets-Sheet 5 INVENTOR MI/Bz/fiMfi Jam/s raw 7 ,VM

ATTORNEY Patented Feb. 25, 1936 UNITED STATES PATENT OFFICE PRESSURE OPERATED REGULATOR FOR BURNERS 26 Claims.

This invention relates to a furnace control device or a control device or regulator for a burner which heats the furnace or other member. Heat treating furnaces used for annealing castings and other objects, forge furnaces, and furnaces of other types are now commonly used, and it is quite important not only to regulate the temperature closely, but at the same time to maintain the right kind of atmosphere in the furnace. It is, of course, also desirable and almost necessary to have a control member or regulator which is automatic. The burners used for heating the furnaces usually use liquid fuel or oil, and air is supplied under pressure for combustion. The control devices and regulators of the prior art have largely used valves for regulating the oil supply. The oil generally used for fuel in said furnaces is heavy and this oil contains numerous lumps or clots of semi-solid matter, as well as some sand or other sediment. When regulation is attempted by closing or partially closing a valve or otherwise diminishing the passage through which the oil passes, the lumps or clots in the oil tend to collect at the restricted point and this action increases until the free flow of oil is impeded. The valves also tend to stick, and it is difficult to move the valve the required distance to give the desired regulation. If such valves are opened to relieve the impeding collection of matter therein, an excess of oil is allowed to pass to the burner, giving a reducing atmosphere in the furnace.

It is also desirable in a regulator or control member for a burner to secure one which is perfectly responsive to the changes in the burner.

' This, of course, is an ideal condition. In most regulators this condition is not attained, as there is a lag between the burner and the regulator due to friction and the mechanical structure and movements of the regulator. Such cases not only cause a lag, but often results in movements of the regulator which are not in harmony or synchronism with the changes in the burner.

It is an object of the present invention, therefore, to provide an automatic regulator for a burner to which both the oil and air supplied to the burner are regulated, and both of which are regulated by a device perfectly responsive to the change in temperature of the burner.

It is another object of this invention to provide an automatic regulator for a burner or furnace in' which both the oil and air supplied to the burner are regulated and the oil is regulated while maintaining the passage through which the oil passes at its regular size, together with means for causing the regulator to be substantially perfectly responsive to the change in the burner.

It is a further object of the invention to provide an automatic regulating device for a burner or furnace comprising an air supply for said furnace and and oil supply means for said furnace, and means for varying said air and oil supply means in accordance with air pressure, which pressure is directly responsive to the temperature in the burner.

It is another object of the invention to provide an automatic control device for a burner comprising means associated with the temperature determining means of the burner or furnace which functions to create a certain air pressure, a means responsive to said air pressure constructed and arranged to move a member which in turn is connected to means for regulating the air supplied to the burner, and means for regulating the oil supplied to the burner.

It is still another object of the invention to provide an automatic regulator for a burner or furnace comprising means associated with the pyrometer or potentiometer of the furnace for determining a fluid pressure directly proportional to the temperature, means comprising a balanced valve responsive to said pressure and having a moving element connected to the means for varying the oil supply and the means for varying the air supply.

It is more specifically an object of the invention to provide an automatic regulator for a burner or furnace comprising means associated with the temperature recording instrument constructed and arranged to build up a fluid pressure in direct ratio to the temperature, means responsive to said pressure including a diaphragm operated means movable in response to said pressure, a member movable by the last mentioned means connected to an air regulating valve and to an oil supply pump, whereby the supply of oil and air may be regulated.

It is also an object of the invention to provide an automatic regulator for the burners of a furnace which will similarly and accurately govern a plurality of burners in accordance with the temperature of the furnace, which regulator can be used to govern the supply of air and oil separately or to govern the supply of air and oil at the same time.

These and other objects and advantages of the invention will be fully set forth in the following description made in connection with the accompanying drawings, in which like reference characters refer to similar parts throughout the several views, and in which:

Fig. 1 is View partly in side elevation and partly in central vertical section through the diaphragm regulator;

Fig. 2 is a View in horizontal section taken on line 2-2 of Fig. 1;

Fig. 3 is a vertical section taken on line 3-3 of Fig. 2;

Fig. 4 is a vertical section taken on line -4 of 2; a

Fig. is an end view as seen from the right of Fig. 2;

Fig. 6 is a view partly in end eievation and partly in vertical section of a pyrometer attachment; v

Fig. 7 is a vertical section taken on line 1-1 of Fig. 6;

Fig. 8 is a vertical section taken on line 8-8 of Fig. 7;

.Fig. 9 'is' a horizontal section taken on line 9-9 of Fig. 8, as indicated by the arrows;

Fig. 10 is a longitudinal vertical section through a pump used; a

Fig.'11 is a vertical section on line ll1ll of Fig: 10, as indicated by'the arrows;

Fig. 12 is a vertical section taken on line l2-l2' of Fig. 11, as indicated by the arrows;

Fig. 13 is a view in side elevation of the arrangement showing the regulator applied to a tively driven as long as the burner to be regu-' lated is in operation. While various kinds of pumps might be used, in the embodiment of the invention illustrated, a pump is shown comprising a casing I9 having a base flange secured to the base member I5, which pump is arranged to be constantly driven but to deliver different,

quantities of oil or liquid. Said pump constitutesa housing lea having a cylindrical chamher in which is fitted a head 20 secured to and adapted to be turned by the shaft [6 extending through a hub projecting from the housing 1912,

Which hub is bored at its end to receive apack-- ing gland 2| adapted toengage suitable packing 22 and press the same about the shaft l6; Said gland 2| has an end flange with grooves there in adapted to be engaged by ribs 230, on a holding and adjusting member 23 through which shaft l6 passes, and which is secured to the hub of the housing l9a' by headed screws (not shown), passing therethrough and threaded into said Head 20 has extending therethrough a transverse cylindrical bore in which is disposed a plunger 25. Plunger 25 has a rectangular groove extending transversely thereof, in which is fitted a'block 26. Said block 26 has a hole formed therein, in which is disposed and rotatable a pin 21 which projects eccentrically from a cylindrical block 28 fitting in the cylindrical bore of a head 29 bolted to housing l9a by the cap bolts 30, which head has a oylindrical portion at its front end adapted to fit in the bore in housing l9a and engage the head 29. A gasket 3| is disposed between the head. 23 and 1101.15-

l9a. The head 29 is bored at its outer end to receive a packing gland 32 adapted to press packing 33 about a shaft 34 which is secured to block 28 and projects outwardly through head 29. Gland 32 has an outer flange with. grooves at the sides thereof into which extend ribs 35a on a holding and adjustable member 35 through which shaft 34 passes and which is secured to gland 32 by the headed screws 36. Shaft 34 extends outwardly from member 35 and has journaled on its outer end the hub of a lever 31. A collar 38 is pinned on shaft 34 at the inner side of lever 31. The housing [9a has at its upper end passages [9b and [9c communicating respectively with semi-annular grooves l9d and He formed in said housing at either side of head 20, and conduits I97 and l9g are secured in housing I9a and communicate respectively with the passages I91:- and I90. Said housing comprises a diaphragm Hit, the space at the under side of which communicates with passage I92),

said diaphragm having an opening therethrough,

in the top of said cap and bears against plunger :97 at its lower end and against the top of said shell at its upper end, thus tending to force ball valve I91 against its seat. The space above diaphragm l9h communicates with the passage I90 as shown in Fig. 11. The lever 31 has a laterally projecting arm 3la which has projecting therefrom intermediate its ends a lug 31b. Another lever arm 3lc is secured shaft 34 outwardly of lever 31, which lever arm 31c hasan arm extending upwardly and laterally toward the outer end of arm 35a and has a hub intermediate its ends in which is threaded a screw 39 having a jamb nut 40 thereon engaging the top of said lug. Said screw has a knurled adjusting wheel 4| at its upper end secured thereto, and the lower end of said screw is rounded to engage lug 3Tb. The lever arm 310 is apertured at its outer end and has secured therein one end of a tensile coiled spring 42, the other end of which is secured to a screw 43 threaded into the base member I5. The outer end of arm 31a is semi-spherical in shape and hason its top a cap 44 having a semi-spherical. recess fitting thereover; A washer or collar 45 is dis=' posed below the semi-spherical end of arm 31a, fitting about its semi-spherical portion, and said collar has its lower side, formed with a semi spherical recess adapted to fit over the semi-j spherical end 46a of the lever 46. A lower cap 4! has a semi-spherical recess fitting about the lower side of the semi-spherical end of lever 46 and arm 31a. and the end of lever 46a are bored to receive the headed bolt'4B which is of smaller diameter than the bore in said members, which bolt also passes through and in the caps 44 and 41 as well as collar 45 carries the nuts 49 at its upper end above cap 44. Lever 46 passes through a lug or collar 50 having projecting laterally therefrom a stem 50a extending through a block 5! and held in'said block by the cotter key 52 passing therethrough. Lever 46 at its other end receives a head 53 s'ecured therein by the pin 54 which is secured by a pin 55 a pair of links 56. The links 56 extend substantially vertically in parallel relae' ticn and are secured at their upper ends by the pin to a head 58 secured by the pin 59 to a vertically movable hollow shaft or tube 60 to be later described. The block 5I is slidable on a screw EI carried in the end arms 62a of a bracket 92 secured to the base I5 by the screws 63. Block 5| is adjustable on the screw GI by nuts 54 of cylindrical form having knurled peripheries which are threaded on the screw GI and engage the ends of block 5! respectively. Said block slides on a rod 625 forming part of bracket 62 and extending parallel to screw 6|. The lower ends of links 55 are connected to the end of a lever arm 55 having a hub secured to a shaft 66a extending transversely of the base I5 and journaled in bearing brackets 66 bolted to each side of said base by the bolts 67. Shaft 66a has secured to each end thereof an arm 68 extending upwardly at the sides of base member I5. These arms 68 are adapted to be connected to links, one of which is shown as 59, connected to the end of one of the arms 68 by the screw IS. A washer a is shown as being disposed beneath the head of screw I5 against the outer end of the hub of link 59. The link 69 extends to adjacent the burner II and has its other end bifurcated and embracing and connected to an air regulating arm Ila. of said burner by the bolt or pin 72.

Bracket I3 is secured to base I5 intermediate its ends and has a plate-like top portion 13a with a downwardly extending central hub 13b and a casing I4 is secured to the top portion 13a. Said top portion and hub 7327 are bored to have the plunger tube 59 pass freely therethrough. Casing I4 has an upper disk-like circular flange and a top casing I5 is supported thereon, having a flange I511 extending about the outer edge of casing 74. A flexible diaphragm I6 is clamped between the edges of casings 74 and I5, said casings and diaphragm being secured together by the circumferentially spaced headed and nutted bolts Il. Casing I5 has an upper portion with ofiset vertical sides which are tapped to receive conduits i8 and I5. An opening 152) extends inward from conduit I8 and opens out at the top of easing I5. Casing I5 has a central cylindrical portion 150 extending vertically therethrough, said cylindrical portion being hollow to have therein the chamber 75d. An opening I5e leads inward from the conduit I9 into the chamber d. The central lower portion of member I5 and the upper end of cylindrical portion 150 are bored to receive slidably the plunger tube 65. Casing I5 also has a short vertically extending cylindrical portion 15f surrounding the lower part of portion 150 and a casing 85 has a cylindrical base fitting tightly about the portion I5f and fitting tightly on the top of casing I5. Casing 85 has at its upper end a disk-like circular flange about which extends a rib or flange 81a of another casing 8|, said rib Bia depending from a circular flange on casing BI overlying the said flange on casing 89, a flexible diaphragm 82 being disposed between said circular flanges on members 85 and 5|, said diaphragm being clamped between said flanges which are connected by the headed and nutted bolts 8-3. The casing 8i has a :ylindrical upper portion 8Ib, which has an op ning 8Icl therein. The diaphragm I5 has a central opening through which extends the conical central portion 840. of a member 84, having a disk-like flange over which the inner edge of the diaphragm I6 lies. Portion 84a. of member 84 is pinned by pin 84b to tube 60.

A washer plate 85 overlies said inner edge of diaphragm l6 and said washer and diaphragm are secured to the flange of member 84 by the screws 86. A compression coil spring 81 engages the under side of member 84 and surrounds a downwardly extending conical hub portion 84b thereof which is bored to have the plunger tube 55 extend therethrough. The lower end of spring 8! rests on the bottom of casing I4 and surrounds an upwardly extending conical hub 14a thereof. The inner end of diaphragm 82 extends over the bottom of a flange projecting from the lower end of a hollow cylindrical member 88 and is secured thereto by the screws 89 which also pass through a washer 9i overlying said diaphragm. A compression coil spring 9i surrounds member 88 having its lower end resting upon the flange at its lower end and the upper of said spring engages a plate 92 having a depending flange 92a, thereon surrounded by the upper end of said spring. Plate 92 has a central aperture which receives a cylindrical projection depending from a member 93 threaded into the central hub 8Ic at the top of portion 8 lb of member 8|. Plate 92 rests against a shoulder formed on the member 93 and a jamb nut 94 is threaded on the upper end of member 93 and engages the top of hub 8Ic. The member 93 is bored to receive a rod 95 which moves therethrough with a free sliding fit, which rod extends downwardly coaxial with the plunger tube 60 and has secured to its lower end a piston 96 which moves with a free fit in the plunger tube 60. Rod 95 also has pinned thereto some distance above piston 95 a second piston 97 also slidable in plunger tube 69 with a free flt. Said rod 95 also has pinned thereto the hub 88a, at the top of member 88, through which rod 95 passes. The upper end of the portion I50 of easing I5 is bored to have the plunger tube 60 slidable therein and said plunger tube is also slidable through the lower end of casing 15. The plunger tube 65 has a plurality of holes 59a therein some-distance below its upper end and also has a plurality of holes 60b therein some distance below holes 60a and has a plurality of holes 600 therethrough some distance below the holes 59b. Casing I4 has one or more openings 14b through the side of its lower cylindrical portion.

The member 8| has a yoke 8Ie with parallel arms extending along the sides of member BI and secured thereto by the screws 81f. Said yoke is bored at its top to have slidable therein a sleeve SIg having a head or flange BIh at its lower end and exteriorly threaded at its upper end to receive a member 8 It having a projecting flange 8| 7' at its lower end. A nut 8H0 is threaded on the top of member Sly and engages member 8Ii to act as a jamb nut. Member My is interiorly threaded to receive the upper threaded end of a hollow plunger rod 8Im which is connected at its lower end to a plunger or piston 8| n. Piston 8m is movable within a dash pot 8Io having secured in the ends thereof flanged closure members 8| p. The lower closure member or head BIp is rigidly connected to the rod 95 by the pin 95a. The plunger SIn has an aperture 8Iq extending therethrough formed at its upper end to constitute a valve seat, and said seat is adapted to be engaged by the valve forming end of a rod 8Ir extending through rod 8Im, said rod 8Ir being threaded into the upper end of member Blm and having a head 8 Is of angular form, the same being shown as square. Rod 8 Im has a plurality of openings 8 It extending therethrough just above the valve seat at the top of aperture 8Iq.

The conduit I9 extends to the air line or a source of air under pressure which is usually on hand to supply air to the burner II. A pipe 19a extends from pipe I9 at one side of member I5 and is connected to pipe 18 which leads from the other side of member I5. 'A regulating valve 19b is disposed in conduit or pipe 190.. Such burners are usually equipped with a pyrometer to indicate the temperature thereof, and in Figs. 1, 6, 7 and 8 a device is shown which will be attached to the pyrometer. While different forms of pyrometers may be used, the particular type illustrated is the well known Leeds & Northrup pyrometer. Such pyrometers have a revoluble dial or other member to adjust them for different temperatures. In Figs. 1, 6, '7 and 8, a shaft I of such a pyrometer is shown, to which is secured a gear IOI adapted to mesh with another gear I02' equipped with means for turning the same to adjust the position of gear IOI. Gear IOI has secured thereto a member I03 journaled on shaft I00 and extending through a substantially cylindrical casing I04. Casing I04 has a chamber I04a therein and has a flange at one side to which is bolted by the bolts I06 a complemental flange Ia of another casing I05. Casing I04 has a hub surrounding member I03. The mem- ;ber I0'I is secured to member I03 by a set screw I08, and another member I09 is secured to the outer end of shaft I00, by the rivet or bolt IIO, said member I09 having a cylindrical flange I09a, the inner edge of which is recessed slightly into the wall of member I0'I fitting against the end of casing I04. The cylindrical flange I 09a thus forms an annular chamber I I I between its'outer wall and the wall of casing I04. Casing I04 has an outwardly extending hub I04b tapped to receive theiconduit I8 which extends from casing 15. Member ID! has projecting across the an- I nular chamber III a pair of blocks or partitions H2 and H3. Member I09 has a plurality of holes I09b formed through its vertical portion within the flange I09a, which holes communicate with a chamber II4 formed in the outer portion of casing I05 and between the outer wall of casing I05 and the vertical portion of member I09. Member I05 has an outwardly extending hub I05b into which is threaded a conduit II5 which will extend to the atmosphere. Member I09 also has an opening I090 extending radially therethrough and this opening has overlying it at the inner side of flange I09a, a plate IIB secured and swingable about a screw III, the shape of said plate being shown in Fig. 9.

In operation motor I8 will be driven and through the coupling I! will drive the shaft I6 of the pump I9. It will be seen from Figs. 10, l1 and. 12 that pin 21 is eccentric to the axis of head 20 and shaft I6. When the head 20 is driven, block 26 slides in the groove in plunger 25 and said plunger is reciprocated in head 20. It will be seen that the eccentricity of pin 21 can be varied by turning shaft 34. Pin 21 can be brought to a position coaxial with shaft I6 and head 20 and when this occurs, plunger 25 will not be reciprocated. When said pin is at one side of the center, plunger 25 is reciprocated and is nearer, one side of head 20 than the other. When pin 21 is at the other side of the center, plunger 25 is nearer the other side of head 20. Pump I9 can therefore be set or adjusted so that oil will be taken in conduit I9 and discharged through conduit Hg in varying amounts or it can be set so that no oil will bedelivered at all. It can also be set so that oil will be taken in at conduit I9g and discharged through conduit I9f.

With the burner operating, the oil is taken in through conduit I9g and discharged through conduit 19]. The pumping action is caused by the oil passing from passage I9c into groove I96 and then:

distance from the end of the bore and when head 20 revolves one hundred and eighty degrees, the end of said plunger will be moved outward toward the end of the bore, thus forcing the oil outward into groove I9d and out through passage I91) and conduit I9,f. The movement of plunger 25 as stated can be varied by adjustment .of pin 21, by turning the shaft 34. The amount of oil delivered can be varied therefore, by turning the shaft 34. It will be apparent that when lever 31 is turned, that shaft 34 will be turned and the discharge from pump I9 varied. It will'also be noted that this variation in the amount of oil delivered is secured without diminishing the oil oil pumped to the burner is diminished. When arm 31a is moved upwardly, the amountof oil pumped to the burner is increased. It will be seen that spring 42 will cause arm 310 to move with arm 31a. when arm 31a moves downwardly, and when arm 31a moves upwardly, lug 31b will engage the end of screw 39 and move arm 31c upwardly.

The amount that the oil is regulated will depend upon the position of the block 5 I. As shown in Figs. 1 and 2, the block is now in its farthest position to the left, so that the end of lever 46 to which arm 31a is connected has its greatest movement. If block 5I be moved to the right by adjustment of nuts 64, then there will be a smaller movement of arm 3112. for the same move- 7 ment of tube 60. It is usually desired to regulate a burner between certain quantities of consumption. If with the setting illustrated it be assumed that the burner was regulated between five and twenty-five gallons per hour, then the movement of block 5| to the right would mean that it would be regulated between five and a lesser number of gallons than twenty-five. Rod 62b is parallel to lever 46 with tube 60 in its highest position and block 5| in the position shown. By having the screw 6| and the rod 62b thus inclined downwardly and parallel, the lower limit of consumption will remain constant, unless screw 39v is adjusted. By turning said screw upwardly away from lug 31b, the lower limit can be set lower and by screwing said screw downwardly to separate arms 31c and 31a, the lower limit can be raised.

Assuming that the burner is operating and being brought up to the desired temperature, shaft I00 will revolve as the temperature increases. This action is usually secured through a thermostat or thermocoupleiin the furnace. As stated, conduit I9 is connected to the blast line and the air pressure used in the blast line is present in chamber 15d and in the chamber in tube 60 between the pistons 91 and 96. The pistons 91 and 96 are fitted to have very little friction, if any, on the walls of the tube 60, but they are fitted to keep the pressure of the blast from passing out of said chambers. Some air, however, will leak past the pistons and this air passing the upper piston will pass into the upper end of member 88 downwardly below diaphragm 82 into passage 15b and conduit 18. This air therefore passes into chamber III of casing I04 at the left of the members H2 and. H3, as seen in Fig. 8. Some air will also be delivered into the chamber III through pipe 19a. This pipe forms a bypass and valve 191) will be adjusted to give the desired amount of pressure and air to be delivered to chamber II I. When the temperature of the burner is low, the opening I090 in portion I09a of member I 09 is near member I I2 which is fixed in relation to casing I04. As the temperature rises, shaft I00 is moved in a counterclockwise direction as indicated by the arrow in Fig. 8, and portion I09a is similarly moved so that opening I090 approaches member I I3. As long as opening I090 is to the left of member II3 as seen in Fig. 8, the air passing into chamber I II through conduit I8 can pass through opening I090 into member I09 through the openings I09b and out through the vent or exhaust pipe I I5. As opening I090 begins to pass member I I3, the outlet for the air diminishes and when opening I090 has passed member II 3, the outlet for the air is closed and pressure will begin to build up in chamber III at the left of and between members H2 and I I3. This pressure will, of course, extend back through conduit I8 and the passage 15b and into the chamber below diaphragm 82. Diaphragm 82 will thus be raised a certain distance corresponding to said pressure, thus raising member 88 and compressing spring 9|. When member 88 is moved upwardly it carries with it piston rod 95 to which it is pinned and said rod in turn moves pistons 91 and 96 upwardly in plunger tube 60. As stated, conduit I9 is connected to the air supply :for the blast and the full pressure of the blast is thus normally present in chamber 75d. When the mechanism shown in Fig. 1 is in the illustrated position, it will be seen that the air under pressure in chamber (501 has no outlet. The pistons 96 and 91 prevent its outlet either down-' wardly or upwardly, the lower piston closing the ports 602). When piston 96 is moved upwardly as described, the ports 60b are partly uncovered and communication is afforded from the top of diaphragm I6 through ports 692), the interior of tube 60 and ports 60c and 14b to the atmosphere. Spring 81 can now act and member 84 and tube 60 to which it is pinned will be pushed upwardly with diaphragm I6 until the ports 6012 again register with the piston 96 and communication is again shut off with the atmosphere when further movement upwardly of member 84 will be prevented. The member 84 thus reaches balanced position when it has moved upwardly exactly the same amount as member 88 has moved, which is the distance that the pistons 96 and 91 have moved. It was found in the development of the device that if the rod 95 was moved freely by the diaphragms, the device was too sensitive and a greater motion than necessary would be obtained. It was then proposed to use a dash pot to regulate the movement of the rod 95 and thus of the pistons 96 and 91. After much experimenting with the dash pot it was found that this would retard the action too greatly. The idea was then conceived of using a dash pot with a lost motion device so that the rod 95 could move freely for a certain distance but would be retarded after having moved this distance. It was for this purpose that yoke 8I'e and member 8Ig were provided. It will be seen that when member 88 is raised by diaphragm 82 and rod 95 is thus raised, that dash pot 8I0, is moved upwardly. The movement of the dash pot is, of course, resisted by plunger 8In, since relative movement of the dash pot and plunger can only take place by the liquid or oil Blu in the dash pot passing the plunger am. This resistance to movement of the dash pot by plunger am causes both the dash pot and plunger, together with rod 8Im and member 8Ig to be moved upwardly until the upper surface of flange 8Ih engages the yoke 8Ie. The upward movement of rod 95 and the dash pot is then checked and any further movement of rod 95 must take place slowly to enable the oil to pass plunger am. The latter portion of the movement caused by diaphragm 82 is quite slow. It will be seen that member 8Ig can be adjusted on rod film and member 8Iz' can be adjusted on member 8Ig. The free movement of rod 95 can therefore be adjusted to be greater or smaller. When tube 60 is moved up by member 84, it carries with it the block 58 and the links 56. Lever 46 is thus swung by the links 56 about its fulcrum 50a and through the connection 48 and associated parts arm 31a is moved downwardly. This turns shaft 34 and the supply of oil as described is diminished. At the same time links 56 swing lever arm and 68 and through the link 69 the air to the burner is cut down by means of a lever Ila. The fuel and air supply to the burner will thus be cut down and the temperature will not continue to rise in the burner or furnace. Should the temperature drop so that member I99a moves back and opening I090 and a portion thereof passes member II3, the pressure will be diminished in the chamber at the left as shown in Fig. 8 between members H2 and II9 and pressure will thus be diminished in the chamber below diaphragm 82. When this occurs, the spring 9I will force member 88 downwardly, thus moving down pistons 96 and 91. The downward movement of member 88 will be free until the lower surface of flange 8|? engages the top of yoke 8| e. The movement will then be retarded by the dash pot 810 so that there will not be an excessive movement of member 88 and thus of rod 95. Downward movement of the piston 96 will uncover the upper portions of ports 60b and the air under pressure in chamber 1511 which is also within the tube 60 between pistons 96 and 9! will pass out through the ports 6% into the chamber above diaphragm I6. Diaphragm I6 will thus have pressure above it and said diaphragm and member 84 will be moved downwardly until the ports 60?) are again closed. When the ports 60b are again closed by piston 96, member 84 again reaches balanced position, and it will thus be moved downward exactly the same distance that member 88 moved downward. Downward movement of member 84 causes downward movement of tube 69 and as described, this movement will regulate the supply of oil and air through lever 46 and link 69 so that said supply will be increased. The temperature will again rise and opening I090 will be moved past member H3. The burner will thus be brought to and maintained substantially at the desired temperature. The regulator is of the type which maintains substantially one temperature instead of the type which works on the high-low principle to maintain the burner between certain limits. The opening I090 is, of course, gradually closed as it moves past member II3. With the described structure, therefore, the burner will gradually come up to the desired temperature and will be maintained substantially at this temperature. It will be seen that the structure comprised in members 58 to 9! constitutes a balanced valve and the movement of the member 60 A caused thereby is directly responsive to the pres-v sure exerted below diaphragm 82. In fact, said diaphragm member 88' and thus pistons 96 and 91 move a certain definite amount for each pres-' sure. The pressure is in eifect measured by the spring 9I. Member 84 as stated moves exactly the same distance upwardly or downwardly as the pistons 95 and 91, and this will be true regardless of the friction of the parts or the load. The air is exhausted above diaphragm 16 or is placed in communication with the atmosphere when it is moved upwardly by spring 81, whiie When it is moved downwardly it is positiveiy moved by the pressure of the air from the source of blast. The diaphragm will be sure to be forced down as it will have the full pressure the blast thereon and diaphragm 16 is of large area. The regulation of the oil'and air is therefore made by the movement of member 60 and this is directly responsive to the pressure in chamber I H which is in accordance with the temperature of the burner. As stated, the pistons 96 and 91 depend in' the tubes 60 and have practically no friction therewith. .Diaphragin'82 and member 88 therefore always take a definite position for a certain pressure. Thisaction is substantially the same as a spring scale using a compression spring". The movement and position of members 82 and 8B is thus independent of any friction. It will also be seen, as has been above described, that member' 84 will be moved exactly the same distance that member 88 has been moved,'regardless of the friction of any parts and regardless of load cenditions. If there is more friction or if some of the parts are inclined to stick, the movement of member 84 may be somewhat retarded, but it must positively move the same distance as member 88.

Twp levers 68 are shown and a plurality of burners can be simultaneously regulated 'by the levers 685 These burners will both be regulated exactly the same amount, The pump can supply oil to two burners. The conduit I9g passing to the burner will have branches leading therefrom to'the burner with regulating valves in each branch. These valves would be pro-- vided to apportion the oil between burners of different capacity.

The regulator can also be used to regulat'e a plurality of burners where the oil and air are separately regulated. In Figs; Band 14 a burner H is shown. The burner has a discharge passage '1Id through which air passes, which air is regulated by the movable members 1Ie. This member is carried on a plurality of rods 1If secured to the member 1Ig which is moved toward and from the burner by the links 1 I it connected to the lever 11a pivoted to a bracket 1Ii. 1Ia is connected by the links I to block 58 already described, connected to tube 60.

secured to portion 1I7 of the burner. 15 as already described is connected'to member 14 and casings 80 and BI are connected above casing 15. Members and the parts thereabove and pipe I24'beyond valve I25 is connected to cas- Lever The 'casing 14 is shown as carried on a bracket I 2| Casing will control the air to the burnerfl.

Another pipe I29 corresponding to pipe I23 (501119.

municates with the pipe I30 which is connected to another casing 15 so that there are two diaphragm controls, each of which includes the parts 14 to 91 shownin Figfl. It will be. under- Member 104 is shown'as associated V stood that each diaphragm control'includes" the members Hand 58 and that there are two sets of links I20'as well as a burner II for eachof the diaphragm controls. A pipe MI is connected to pipe I24 and has a pipe I32 leading therefromwhich communicates with member 15 and specif ically to chamber 15b thereof as shown in Fig. -1. Pipe I22 as well as pipe I32 communicates with passage 15a in member15; Another pipe I33 leads from pipe I2 and communicates with the pipe I34 cennected to member15 of the'other diaphragm control shown in Fig. 14 and pipe I34 also communicates with passage 15b of mem-f ber 15. A pipe I35'extends from pipe I3I and'this pipe communicates" with chamber 15b of a member 15' of' another diaphragm control adapted to control the oil to the'two burners 1I. Pipe I23 alse'extends to member 15 of the oil control diaphragm and this is connected to chamber 15e.of said member .15. 7 thebottom of Fig. 14 comprising the parts to 91 "will be designated I36, while the diaphragm control. shown at the top of Fig. 14fwill be designated I31 and'the diaphragm control for controlling the oil to the two burners will be designated I38. The diaphragm controll38 has its' tube 60 connected to leverj4$ as shown in Fig. 1 and. pump I 9, motor i8, and base member I5 are shown as shown in Fig. 1, and the parts will be connected as shown in Fig. 1 except that links 56' will not be connected to arm 65, which arms will be'omitted as wili alsoparts 55, 61, 68a'nd 69. Otherwise the pump control is the same as shown in Fig. L'The outletof the pump has a pipe I40' connected theretowhich is connected by ia'suitable T to branchf pipes MI and I42, each of The diaphragm control shown at;

which has therein a valve :43. Pipes m and I42 are connected respectively to the supply oil thereto:

"With the arrangementshown in Figs.

burners II and stantly present'in chamber 15d of member 15. Reduced pressure is supplied to pipe I24 beyond valve l26 and this pressure passes into member IE4 and is exhausted through opening I0c andpipe I21 until'opening I090 as already described,

passes member H3. This reduced pressure then btul-ds up in chamber I I I and is transmitted into movement of member lfi lai just as do the dia phragm members wfi and I31. The dianhrasms 1 3 and 14, the pressure carried in the blast will be con- 52 and members 88 in each of the diaphragm controls will therefore be moved to certain definite positions by the pressure developed in member H14. The springs 9:! will, of course, be very nicely adjusted so that they are the same in each control. The pressure developed in member H14 will therefore produce exactly the sameresults in movement of the member .88 in each of the diaphragm .controls and the diaphragm 76 and member 8d will be moved in each diaphragm control exactly the same distance which will be the same distance that member .88 is moved or a distance in fixed ratio to the distance that mem ber 88 is moved. The .oil and air for each burner will therefore be accurately controlled directly responsive to the temperature in the furnace and this, control will be had regardless of the friction of the parts or the resistance due to the work done in moving the parts. It will readily be seen that any number of burners can therefore be controlled and that the movement of member 6!] will be exactly the same for each burner. It will also be seen that if desired, a pump can be used for each burner instead of having one pump for both burners. In such case the connection from lever would extend to the arm 31a of each pump instead of just to one pump. It will also be noted that the pump furnishing oil to one burner may be adjusted so that a certain movement of arm 31a would control the pump between different limits than the same movement would control the pump for another burner. One burner in the furnace might be located close to the door and it would be desired to supply more oil to this burner. It might be stated that the valves M3 in the pipe lines Mi and M2 leading to the burners are merely to control the relative amounts of oil which pass to the burners.

From the above description it is seen that applicant has provided a simple and efficient control or regulator for a furnace and the burners thereof. As above stated, a practically frictionless primary control is used which is directly responsive to the pressure developed by the temperature of the burner. This primary control member controls a power control and this is constructed and arranged to move in fixed ratio to the movement of the primary control regardless of frictional or work resistance. An accurate and positive control of the burner is thus secured. As above described the regulator or control is applicable to a plurality of burners and every burner will be accurately controlled in direct response to the pressure developed at the pyrometer device. The temperature of the burner will, of course, be determined by adjustment of member H3 which is carried on member I81, in turn carried on member I03 turned by the gear lGi. Plate H6 can be moved entirely off of opening H390, or it can be moved over said opening as shown in Fig. 19. The shape of opening I090 can also be varied. The greater the area of opening H390 affected by a certain movement of portion 559a, the more sensitive will be the control. If the opening I090 were rectangular with a long dimension extending parallel to the shaft IE9, a slight movement of member lflQd would mean quite a large closing movement or effect of opening I090. It is not desirable, however, to have the regulator too sensitive as this means that it will move too far for very small temperature changes and the temperature graph would move quite a distance at each side of the desired temperature line. By having a lesser area of opening l 090 affected by a small movement of member I09a, the temperature line is kept almost in a straight line. The burner comes up .to the desired temperature and the pressure created by the position of opening 190 is responded to by the diaphragm control and the burner is held approximately at one temperature.

It will :be understood that when the furnace is cold or at low temperature, the spring 9| forces diaphragm '82 or member 88 to substantially their lowest position. When the furnace reaches the desired temperature and the pressure is created in chamber I I I, this pressure as described acts on and raises diaphragm 82 and the diaphragm control balances at the proper point to hold the furnace at one temperature. The parts are illustrated in Fig. 10 in an intermediate position.

The device has been amply demonstrated in actual practice and found to be very successful and efiicient. It is obvious that it is readily applicable to any burner using oil or other liquid fuel and/or air for combustion.

It will, of course, be understood that various changes may be made in the form, details, arrangement and proportions of the parts, without departing from the scope of applicants invention, which generally stated, consists in a device capable of carrying out the objects above set forth, in the parts and combinations of parts disclosed and defined in the appended claims.

What is claimed is:

1. Means for regulating a furnace heated by a plurality of burners, having in combination, a plurality of burners, means for creating a pressure in accordance with the temperature of said furnace, a plurality of members each movable a certain distance by said pressure, a plurality of other members, one for each of said first members respectively movable a distance in fixed ratio to the movement of said first mentioned members, and means for regulating fluid supplied to said burners actuated by some of said other members, and means for regulating the air to said burners actuated by the remainder of said other members.

2. A regulator having in combination, a member movable with substantially no friction, a diaphragm surrounding and attached to said member adapted to be moved by air pressure in one direction, a spring against which said member is moved, a second diaphragm coaxial with said member adapted to be moved in one direction by air pressure, a spring for moving said second member in the opposite direction, a valve part carried by said first mentioned member, a cooperating part carried by said second diaphragm, said parts being adapted to be moved out of registry by movement of said first mentioned member and into registry by movement of said second diaphragm whereby said second diaphragm is moved in fixed ratio to the movement of said first mentioned member, means creating a pressure in accordance with the temperature produced by a burner for moving said first mentioned diaphragm and member, and means for regulating the fuel supplied to said burner and/or the air supplied to said burner actuated by said second member.

3. A regulator having in combination, a freely movable member, a diaphragm for moving said member and coaxial therewith adapted to be actuated by fluid pressure, a spring against which said member is moved and for moving said member in the opposite direction, a second member, a diaphragm for moving said second member in one direction by fluid pressure, a spring for moving said second member in the opposite direction and opposite to the direction said first mentioned diaphragm is moved by said first mentioned spring, means causing said second member to be moved a distance in fixed ratio to the movement of said first mentioned member, means for creating a pressure in accordance with the temperature produced by a burner for actuating said first mentioned diaphragm, and means for increasing or decreasing the air and/or fuel supplied'to said burner actuated by the movement of said second member. 7 p r 4. A'regulatorfor an operative device having in combination, arelay diaphragm adapted to be moved by fluid pressure, means for balancing said diaphragm against said fluid pressure and for moving it in the opposite direction, a power diaphragm adapted to be moved in one direction by fluid pressure, a spring for moving saidpower diaphragm in the opposite directionand' infa direction opposite to the movement of said first 4 mentioned means, means causing said power diaphragm to move a distance in fixed ratio to the movement of said. relay diaphragm regardlessof friction or load resistance, means for creating a pressure in accordance with the temperature produced by a burner for moving said relay diaphragm, and means actuated by said power diaphragm for regulating said device.

5. Means for regulating a furnace heated by a plurality of burners, having in combination, a

plurality of burners, means for supplying fuel to respectively, means for moving said last.men-.

tioned members, and means for increasing. or decreasing the supply of air to said burners operated by said last mentioned: members.

6. A regulator for a furnaceiheated by burners having in combination, means movable in accordance with the temperature of said furnace,

a member movable to vary the supply of fuel to said burner, a lever connecting said means and member for moving the latter, a fulcrum member for said lever movable lengthwise thereof and a rigid guide means for said fulcrum member.

'7. A regulator for a furnace heated by burners having in combination, means movable in accordance with the temperature of'said furnace,

a member movable to vary the supply of fuel'to.

said burner, a lever connecting said means and member for moving the latter, a movable fulcrum for said lever, a guide member for said fulcrum extending parallel to a position of said lever with one end of said lever at its limit of movement."

8. A regulator for a burner having in combination, a member movable in accordance with the temperature produced by said burner, a member having a chamber therein, means for producing fluid pressure in said chamber, means connected to said first mentioned member for closing said chamber to cause pressure to increase therein, a second chamber, a diaphragm in said chamber movable in one direction by fluid pressure in said chamber, means connecting said chamber to said first mentioned chamber, a third chamber,

a diaphragm in'said third chamber'movable. by fluid pressure therein, aivalve mechanism connecting saidsecond and third chambers having a movable member connected to said first memtioned diaphragm whereby fluid may pass from said second chamber to, said third chamber, a member connected to said second .mentioned diaphragm and movable thereby, and means for varying the oil and/ or air supplied to said burner movable by said last mentioned member.

bination, means for creating an air pressure at l0 9. The structure set forth in claim 8,each of' a certain temperature created by said burner, a

member movable a certain distance in one direction' in response to saidair pressure, a constantly acting means for moving said member in the opposite direction when said pressure is diminished,

a second member movable in one direction by air 7 pressure, a second constantly acting means for moving said second member in the opposite direction when said pressure is diminished and acting in the direction opposite to said first mentioned constantly acting means, cooperating means connected respectively to said first and second members for causing said second member to. be moved in fixed ratio to the movement of said first mentioned member and means connected to said second member for-regulating the supply of air and/or fuel to said burner.

11. A regulator for a burner using fluid fuel and to which air is supplied having in combination, a chamber associated With said burner, means for creating a pressure in said chamber at a certain temperature produced by said burner, a flexible diaphragm in said chamber, a balanced valve including a pair of spaced pistons movable as a unit, means connecting said diaphragm to said valve whereby said'valve is unbalanced by said pressure, means for again balancing said valve including a flexible diaphragm and a'member having ports moving into alinement with.

. said pistons respectively, a member moved'inthe balancing of said valve and air and fuel regulat ing means actuated by said member.

' 12. A regulator for a burner using fluid fuel and ,to whichair is supplied having in combination, a chamber associated with said burner, means for creating a pressure in said chamber at a certain temperature produced by said burner,

a diaphragm in said chamber operated in one,

direction, by said pressure, a spring for moving said diaphragm in the opposite direction, a second chamber, a second diaphragm in said second chamber constructed and arranged to be, moved in one direction by pressure, automatically acting means for moving said second, diaphragm in the opposite direction and cooperating means connected to said diaphragms respectively whereby said second diaphragm is moved in fixed ratio to said first mentioned diaphragm regard-r less of friction and load conditions and air and a'cyIinder-in-which said piston moves having a port adapted to cooperate-with-saidpiston, a secsecond 'diaph'ragm, a spring for moving said sec-- ond diaphragm in the opposite direction and means connecting said first mentioned member and saidcylinder;

14." A regulating-devicehaving in combination, a member-adapted to be-moved to regulatean operatingunit; a chamber, a diaphragm in said chamber-movable in one direction by fluid pressure in said chamber; a springadapted to move said diaphragm *in'theopposite direction, amember connected to said diaphragm having I spaced pistons thereon and movable in both directions therewith; a cylinder in which said pistons move having ports adapted to cooperate respectively withsaid' pistons, a second chamber, a-second diaphragm in said'second chamber adapted to be moved'in one direction-by fluid pressure in said second chamber and connected to said cylinder,-a'spring for moving-said second diaphragm inthe opposite direction and means connecting ,said firstmentioned member and cylinder.

Aidevice-of 'theclass described having in combination; amember to be actuated for regulating an operative device,- a-diaphragm movable in-one direction to-certain positions responsive to certain conditions of I said operative device, means for moving-said diaphragm in the opposite-direction, a second -member movable independent-ly'ofsaid diaphragm and positively connectedito said 'firstmentioned member, a second diaphragm-movable in one direction by fluid pressure, means formoving said second diaphragm intheopposite direction and cooperat ing-m'eans comprisingapairof spaced pistons movable withbne diaphragm and a cylinderwith spaced ports movable I with the 1 other diaphragmfor causing said-second member and said second diaphragm -to move-in fixed ratio to -the movement of said first mentioned diaphragm;

16: A lregulator 'for afurnacehaving in combination; amem ber moved as the temperature of said furnace-increases, a-chamber, means for delivering air to said chamber, said chamber having an" outlet closed-by the movement of able in one direction-by said pressure, a spring opposing said movement and acting to move said diaphragm in the opposite direction, a third chamber, a second diaphragm in said third chamber movable in one direction by pressure, a spring for moving said second diaphragm in the opposite direction, a member secured to said first mentioned diaphragm movable to relieve the pressure in said second chamber at one side of said second diaphragm whereby said second diaphragm is moved by said second mentioned spring and means for stopping the movement of said second diaphragm when the same has moved the same distance as said first diaphragm was moved.

1'7. A regulator for a furnace having in combination, a chamber, a diaphragm in said chamber movable in one direction by air pressure, means opposing said movement and acting to move said diaphragm in the opposite direction, said chamber being closed except for means for supplying air thereto and means for exhausting air therefrom, a second chamber, a second diaphragm in said second chamber movable in one direction by pressure, means opposing such movement and acting to move said second diaphragm in the opposite direction and in a direction opposite to that in which said first mentioned diaphragm is moved by said-first mentioned means, means for obstructing said exhaust means-when the'furnace reaches a certain temperature to create a'pressure in saidfirst mentioned chamher and move said first mentioned diaphragm, means connected to said first mentioned diaphragm and 'mova-ble' thereby permitting a release of pressure from one side of said second diaphragm whereby said second diaphragm is moved by saidsecond; mentioned means, means for stopping the movement of said second diaphragmwhen it has moved the same distance as said first mentioneddiaphragm and a regulating member connected to said second diaphragm.

18; A regulator'fora furnace'having in combination, a chamber, a diaphragmin said chamber movable in one direction by air pressure, means opposingsaid' movement and acting to move said diaphragm in the opposite direction, said chamber-being closed except for means for supplying air thereto and means for exhausting air therefrom, a second chamber, a second diaphragm in said chamber movable in one direction by pressure, means opposing such movement and actingto move said second diaphragm in the opposite direction and in a direction oppositet'othat in which said first mentioned diaphragm is moved by said flrstmentioned means, means for'obstructing said exhaust means when the furnace reaches a certain temperature to create a pressure in said first mentioned chamber andmove saidfirst mentioned diaphragm, a membenconnected to said first mentioned diaphragm comprising a piston, a member connected to said second diaphragm comprising a cylinder having a port'with which said piston cooperates, said piston uncovering said port in .the movement of saidfirst mentioned diaphragm and said second mentioned means moving said second diaphragm tomovesaid port into registry with said piston whereby the movement of said second diaphragm is stopped and a regulating means connected to said second diaphragm.

19. A regulator for a furnace having in combination; a chamber, a diaphragm in said chamber' movable in one direction by air pressure, means opposing said movement and acting to move said diaphragm in theopposite direction, said chamber being closed'except for means for supplying air thereto and means for exhausting air therefrom, a second chamber, a second diaphragm in said chamber movable in one direction by pressure, means opposing such movement and acting to move said second diaphragm in the opposite direction and in a direction opposite to that in which said first mentioned diaphragm is moved by said first mentioned means, means for obstructing said exhaust means when the furnace reaches a certain temperature to create a pressure in said first mentioned chamber and move said first mentioned diaphragm, a member connected to said first mentioned diaphragm comprising a. pair of spaced pistons, a cylinder connected to said second diaphragm having spaced ports with which said pistons respectively cooperate and a regulating member connected to said second diaphragm.

20. The structure set forth in claim 1'7 and means resisting the movement of said first'mentioned diaphragm after a certain V movement thereof. 7

"21, A regulator for a-burner having in combination, a member movable to regulate the supply .of fuel and/or air to said burner, a balanced structure for moving said member comprising a chamber, a flexible diaphragm therein movable in one direction by air pressure, a spring resisting said movement and acting to move said diaphragm in the opposite direction, means for supplying air to said chamber at one side of said diaphragm, means for exhausting air from said chamben a second chamber, a second diaphragm in said second chamber adapted to bemoved in one direction by air pressure, a spring for moving saidsecond diaphragm in the opposite direction, means for obstructing said exhaust means when the temperature of said burner reaches a certain point thus creating an air pressure in said "first mentioned chamber to move said first mentioned diaphragm and cooperating means carried by said diaphragms whereby said last mentioned spring moves said second mentioned spring a distance equal to the movement of the first mentioned diaphragm.

' 22..Means for regulating a furnace heated by V a plurality of burners having in combination, a plurality of burners, separate means for supplying fuel to said burners, means" for creating a fluid pressure inxaccordarice with the temperature of said furnace,'a second means including a flexible diaphragm for each burner responsive to said created pressure and movable to a certain position thereby, a member :for each of said second opposing the movement of said diaphragm and acting to move it in a direction opposite to that by which it is moved by said pressure, a member operated in response to the movement of said diaphragm and movable relatively thereto but in a fixed ratio to the movement of said dia-' phragm, a rigid member connected to said mem her and means pushed and pul ied upon by said rigid member and means connected to said last 2.0.32.2, V c i mentioned m s fo y n ihej mo ntj f' fueland air delivered tosaid burner.

24. An'apparatus for controlling the temperature of a furnace heated by ajburner; using fuel and air having in combination, a; chamber; means for creating amressure in said chamber, in ac:

cordance with the temperature of said furnace, a diaphragm to which said pressure is; trans mitted moved by said pressure, resilient means opposing themovement of said diaphragmend acting to move it in a direction oppositeto-j'that by which it is moved by said pressure, amemberr operated in response to the movement of'said diaphragm and movable relatively theretobut in a fixed ratio to the movement of said diaphragm, a rigid member connected: to said meme 1 ber, means moved by said rigid memberiforgvary ing the amount of fuel and air delivered to said burner; a dashpot for controlling the movements of said diaphragm and means bringing saidda'sh pot into operation after a certain movement of said diaphragm.

25. A device of the class describedhavingin combination, a member to be actuated for regulating an operative device, a fiuid actuated diaphragm movable to certain positions responsive to and determined by certain conditions ofifsaid operative device, a third member movable inde-,

pendently of said diaphragm and positivelycone nected to said first mentioned member to move the same in opposite directions, means for moving said third member relatively to but in fixed ratio to the movement of said secondmentioned 1 e r, movement of said diaphragm and meansbringing said retarding means into operation after said diaphragmhas moved a certain distance;

retarding means/ for retarding the 265A regulatorfor a furnace having aburner using :fuel and air having in combination, means movable in opposite directions for varying the fuel and/or air supplied to said burner, arigid means connected to said means for pdshing and pulling thereon to move the same in opposite directions, a chamber through which air is passed, means for obstructing said air in accordancewith the temperature'of said furnace so that a pressure is produced in said chamber, means in said chamber movable in one direction by said air, a spring opposing said movement and acting to move said means in the opposite direction and means responsive to the movement of said last.

mentioned means movable reiatively thereto but member.

WAYBURN E. JOHNSTON.

in fixed ratio thereto connected to said rigid i 

